From mboxrd@z Thu Jan 1 00:00:00 1970 From: Shamile Khan Date: 04 Feb 2004 18:15:14 -0500 Subject: [U-Boot-Users] environment not being used In-Reply-To: <20040204203054.9EEA6C10A3@atlas.denx.de> References: <20040204203054.9EEA6C10A3@atlas.denx.de> Message-ID: <1075936515.1553.21.camel@localhost.localdomain> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de On Wed, 2004-02-04 at 15:30, Wolfgang Denk wrote: > In message <1075855660.7664.95.camel@localhost.localdomain> you wrote: > > > > Just as a follow up, I conclude that U-boot treats flash reads exactly > > as sdram reads i.e. 32-bit accesses. So its not just about the > > This is not correct. > > U-Boot accesses the flash just the way how you configure your memory > controller for flash accesses. Exactly. The memory controller is in FPGA. Its been configured to have a data bus width of 8 bits to the flash memory device. Consequently if a 32 bit access is requested, the first 8 bits are fine and the rest are garbage. > > > to flash e.g md, imiinfo, bootm etc. A hardware fix (an 8-bit bus to our > > byte-mode flash chip) seems like the right way to go. > > Either you or me must be missing something. Why don't you just > configure U-Boot for a 8 bit flash device then? I do have the flash device configured as an 8-bit device and flash memory writes are for byte mode in the flash driver. So writes to flash are fine as long as I use cp.b instead of just cp. As far as reads are concerned, since the flash device is in byte mode I can only access 8 bits in one flash memory read cycle. However U-boot commands like md, bootm, iminfo, crc32 etc access 32 bits in one flash memory read cycle (md.b is an exception). So those commands would work if I have for example 4 byte-mode flash devices and the memory controller concatenates the data thats read from those devices. But I only have one byte-mode flash device. > Best regards, > > Wolfgang Denk > > -- > See us @ Embedded World, Nuremberg, Feb 17 - 19, Hall 12.0 Booth 440 > Phone: (+49)-8142-4596-87 Fax: (+49)-8142-4596-88 Email: wd at denx.de > Real Programmers always confuse Christmas and Halloween because > OCT 31 == DEC 25 ! - Andrew Rutherford (andrewr at ucs.adelaide.edu.au) >